(mini-rhizotrones) down to a soil depth of about 60 cm. These tubes were placed in plots where summer air temperatures and winter snow precipitation were experimentally increased. By taking repeated pictures at the same location, we can collect information on root parameters such as length, surface area, diameter, and their changes over time. Based on that, we can estimate trends in root growth and phenology during the growing season. This allows us to investigate the effects that climate change and indirectly, changes in growing season length, may have on root dynamics in the Arctic. During the 2014 growing season, we used a rotating scanner to collect over 300 highresolution images of the soil surrounding the outer part of the tubes. Based on these images, more than 10,000 roots have been identified and digitized. In the warming plots, which were equipped with small open greenhouses, air temperature increased at the soil surface, whereas the temperature of the soil underneath was not altered due to a continuous lateral flow of cold melting water. Despite this, when we compared the output of the images collected at ambient temperatures with those at the warming plots, we noticed that in the latter, the number of the roots, as well as their length, doubled. We did not expect such a fast response after a year of treatment! Seemingly, the positive effect of increased surface air temperature on plants photosynthesis triggered allocation of resources belowground. Roots lengthened almost to the interface between the active layer and permafrost, exploiting an increased volume of soil in order to scavenge nutrients. Due to the fact that sedges have a root system which functions as a passive gas conduit between the soil and the atmosphere, an increase in root length could ease the transport and emission of methane (CH4) produced in the deeper layer of the soil. On the other hand, once the roots decay as litter, the cold soil temperature and the slow decomposition rates could favor the accumulation of organic C in the soil. Indeed, unraveling root An example of a soil image collec ted at a depth of 20 - 4 0 cm in the wetland on Disko in summer, 2014. It is possible to dis tinguish the white roots of the sedges growing along the outer par t of the tube. Photo: Ludovica D Imper io. dynamics it is a challenging task. By following root growth between July and September, we further improved our knowledge of root phenology. The below-grounds peak in growth was synchronous to that above-ground, but roots kept on growing until mid-September, when the air temperature dropped to 0C, while the photosynthetic activity ceased. In a changing climate, increased temperatures during spring and fall could vary the length of the growing season and lead to a marked difference in growths timing between the above- and below-ground plant biomass with consequences for the net ecosystem C fluxes. We started this project with several questions to be answered and hypotheses to test. After a year of in situ manipulations and a growing seasons worth of measurements, we obtained many interesting results which highlight how fast this ecosystem might respond to changes in temperature and precipitation regimes. Our focus now is to investigate the effects of climate change on root dynamics in the long term and relate them to the other ecosystem processes being addressed in CENPERM focusing on an improved estimation of the net C balance of the Arctic. CENPERM Annual Report 2016 11 ANNUAL REPORT 2016 CENPERM Center for Permafrost Field sites Brønlundhus Svalbard Longyearbyen Greenland Zackenberg Disko Qajaa Sweden Kangerlussuaq Nuuk Narsarsuaq Abisko Sermilik Directors welcome The vision of Center for Permafrost Highlights 2016 Højdepunk ter 2016 Plant root dynamics in a wetland tundra Publications & conferences Communication & outreach Educational activities Ongoing research projects & graduate students International collaborators & funding CENPERM staf Photo: Bo Elberling 2 CENPERM Annual Report 2016 Directors welcome The year 2016 has been an evaluation year, which means that we have been through a midterm evaluation of the Center for Permafrost (CENPERM) and have prepared a revised research plan for 2018-2022. The Danish National Research Foundation has invited us to initiate contract negotiat The vision of Center for Permafrost Microbial activity Plant ecology CENPERM Permafrost soil & landscape dynamics CENPERM integrates multidisciplinary research of biogeochemical and physical processes in a climate-vegetation-soil-microorganismpermafrost approach in transects across the major cli Photo: Kent Pørksen CENPERM Annual Report 2016 5 Highlights 2016 Highlights of 2016 include intensive fieldwork on land and sea, as well as detailed laboratory experiments at CENPERM in Copenhagen. The following four papers published in 2016 highlight the benefits of taking a multidisciplinary approach to the work. 1. The concentration of methane ing the flocculation mechanisms when examining fluxes of meltwater transported iron in polar regions today and in the future, and underlines the influence of terrestrial hotspots on the nutrient and solute cycles in Arctic coastal waters. 4. Generating meaningful greenhouse gas (GHG) emissions targe Højdepunkter 2016 Højdepunkterne i 2016 inkluderer intenst feltarbejde til lands og til vands, kombineret med detaljerede laboratorieeksperimenter ved CENPERM i København. Følgende fire artikler fra 2016 understreger fordelene og styrken ved at arbejde multidisciplinært. 1. Koncentrationen af metan jern i polare egne studeres i dag og i fremtiden, og fremhæver betydningen af terrestriske hotspots i forhold til kredsløbene af næringsstoffer og opløste stoffer i de kystnære arktiske farvande. 4. Udpegningen af meningsfulde mål for udledningen af drivhusgasser (GHG) kræver forståelse af dynamikke Plant root dynamics in a wetland tundra by Ludovica DImperio, postdoc, CENPERM, University of Copenhagen Tundra plants have developed unique characteristics in order to endure extreme environmental conditions including low air temperatures, a short growing season, and limited nutrient availability. (mini-rhizotrones) down to a soil depth of about 60 cm. These tubes were placed in plots where summer air temperatures and winter snow precipitation were experimentally increased. By taking repeated pictures at the same location, we can collect information on root parameters such as length, surface Publications & conferences Blok, D., Elberling, B., Michelsen, A. (2016). Initial stages of tundra shrub litter decomposition may be accelerated by deeper winter snow but slowed down by spring warming. Ecosystems 19, 155-169. Cameron, K.A., Stibal, M., Zarsky, J.D., Gözdereliler, E., Schostag, M., J Lindwall, F., Schollert, M., Michelsen, A., Blok, D., Rinnan, R. (2016). Fourfold higher tundra volatile emissions due to arctic summer warming. Journal of Geophysical Research: Biogeosciences 121, 895-902. Lindwall, F., Svendsen, S.S., Nielsen, C.S., Michelsen, A., Rinnan, R. (2016). Warming increa Rousk, K., Sorensen P.L., Michelsen, A. (2016). Nitrogen transfer from four nitrogen-fixer associations to plants and soils. Ecosystems 19, 1491-1504. Semenchuk, P.R., Christiansen, C.T., Grogan, P., Morgner, E., Elberling, B., Cooper, E.J. (2016). Long-term experimentally deepened snow decreases gr Book chapters Elberling, B. (2016). Le pergélisol face au changement climatique. In: Le Groenland. Climat, écologie, société. CNRS Editions, 77-82. Hasholt, B. (2016). Sediment and solute transport from Greenland. In: Beylich, A.A., Dixon, J.C., Zwolinski, Z. (ed.) Source-to-sink fluxes in undisturb Zhou, Y., Zhang, W., Rinne, J. (2016). Temperature dependency of the correlation between secondary organic aerosol and monoterpenes concentrations at a boreal forest site in Finland. Fall Meeting, American Geophysical Union (AGU), San Francisco, USA, Dec. 12-16. Presentations at conferences, sympos Zhang, W. (2016). Modeling the impacts of permafrost thawing on long term greenhouse gas exchange in Northeast Greenland. Workshop on CoupModel, Use and Calibration, Seminar day in Uppsala, Swedish University of Agricultural Sciences, May 16-17. Zhang, W. (2016). Modeling the process-basedcontrols Communication & outreach April 2016 the book The ice-free Greenland - from molecules to landscape was published. The book is a tale of the ice-free landscape with a focus on how the bio- and geosciences in recent years have provided new, fascinating and surprising knowledge based on the first 100 pu Priemé, A. Permafrost in a changing world. Lecture for high school classes (Roskilde Gymnasium and French high school), May 12. Priemé, A. Permafrost i en varmere verden. Lecture for high school class, KVUC, Oct. 14, Roskilde Gymnasium, Nov. 28. Please see the additional links on our website: www.ce May 12. Jarmo Holopainen, Department of Environmental and Biological Sciences, University of Eastern Finland: Do insect outbreaks on mountain birch affect capacity of subarctic vegetation to form secondary organic aerosols. May 12. Sebastian Zastruzny, M.Sc. student, CENPERM/IGN: Permafrost distribu Guests Throughout 2016, CENPERM has had the pleasure of welcoming a number of visiting experts at the Center. These guests contributed significant scientific insights to the continued research efforts at the Center for Permafrost. Carly Phillips, University of Georgia, US. Research collaboration, co Educational activities CENPERMs activities in 2016 include a number of educational efforts. These include both arctic field courses and classic university courses at the basic and advanced levels at the University of Copenhagen. In addition to course taught, a number of M.Sc. theses have been superv Teaching at the M.Sc. level Advanced bacteriology 2, Dept. of Biology, University of Copenhagen, autumn, A. Priemé. Arctic biology, Dept. of Biology, University of Copenhagen, spring, R. Rinnan, A. Michelsen, A. Priemé. Climate change and biogeochemical cycles. Dept. of Biology, University of Copenh Ongoing research projects & graduate students In 2016 we continued the now nearly-a-tradition of a WriteCamp for the PhD students in November outside Copenhagen. Like the previous years a special Master theses workshop was held in March with discussion and presentations of projects in progress. A nu Jammet, Mathilde M.: Comparative studies of methane dynamics in permafrost environments. Defended Dec. 2016. Supervisor: Thomas Friborg. Lindwall, Frida: Emission of Biogenic Volatile Organic Compounds in the Arctic: The Effect of Climate Change, Defended May 2016. Supervisor: Riikka Rinnan. Markuss Fenger-Nielsen, Rasmus: Predicting and mapping environmental threats to archaeological sites in Greenland under current and future climate conditions. Supervisors: Bo Elberling, Jørgen Hollesen and Aart Kroon. Karami, Mojtaba: Upscaling and modelling ecosystems in permafrozen soil environments. Supe Permin, Aya: Moss responses to climate change in the Subarctic. Supervisor: Anders Michelsen. Simonsen, Anne Mette Tholstrup: Metal speciation and bioavailability of heavy metals from mine tailings deposited in Bøkfjorden, Norway. Supervisor: Bo Elberling Simonsen, Lisbeth: Microbial succession and Rasmussen, Laura Helene: Thermal properties for simulating consequences of changes in thermal regime of deep permafrost layers in Greenland, completed, Jun. 2016. Supervisor: Bo Elberling. Riis, Michelle Cruz: Methane uptake and a landscape integrated methane budget at Disko (West Greenland), comple Svendsen, Sophie Sylvest: The effect of temperature on isoprene emissions from a wet ecosystem in Greenland, completed Jan. 2016. Supervisors: Riikka Rinnan, Frida Lindwall and Ole John Nielsen. Wulff, Katrine: Plant controlled methane production and emissions from a wetland at Disko, W. Greenland, International collaborators & funding Research activities at CENPERM are linked to a number of well-established international arctic networks. These cooperation agreements are supplemented by a strong affiliation to internationally recognized researchers. External experts and Center evaluation CENP International research partners and co-operators Adam Mickiewicz University, Poznan, Poland: Agata Buchwal. Alfred Wegener institute, Germany: Heidrun Matthes, Annette Rinke, Akperov Mirseid. Regional extreme, Arctic Cyclone. Agriculture and Agri-Food, Ottawa, Canada, Shared fieldwork, North Greenla University of Edinburgh, School of GeoSciences, UK: Isla Myers-Smith, Sandra Angers-Blondin; pan-arctic shrub growth meta-analysis. University of Helsinki, Department of Forest Sciences, Finland. Kristiina Karhu. Climate impacts, soil geochem. University of Lund, Sweden. Ben Smith, Paul Miller, Mart Danish Council for Independent Research, Natural Sciences, FNU: Nitrogen fixation as a key function in contrasting ecosystems: Grant holder: Anders Michelsen. Period: 2016-2019. DKK 2,416,251. Danish Energy Agency (Energistyrelsen): DiskoBasis Ecosystem monitoring, partly funding salary for one sci CENPERM staff Researchers Albers Christian Nyrop Researcher Ambus Per Professor Andersen Thorbjørn J. Professor Elberling Bo Professor, Director Ernstsen Verner Brandbyge Associate professor Friborg Thomas Associate professor Hansen Birger Ulf Associate professor Hollesen Jørgen Seni CENPERM staff McConnell Alistair PhD student Nielsen Cecilie Skov PhD student Ravn Nynne R. PhD student Schostag Morten Dencker PhD student Svendsen Sarah H. PhD student Technical staff Jacobsen Pia Laboratory technician Madsen Mathias Electronics technician Moser Vagn Laboratory techni ANNUAL REPORT 2016 The Danish National Research Foundation (DNRF) is an independent organization established by the Danish Parliament in 1991 with the objective to promote and stimulate basic research at the highest international level at the frontiers of all scientific fields. The Center of Excell